NES or SNES all in one systems

Anything like that would be sorta unofficial, grey market type stuff. It's not legal to take all the ROMs (the game data) and sell them preloaded in a piece of hardware, but people do still make those products. I'm guessing the quality could be janky or hit and miss as well. The advantage of course is that you'd get a ton of games in one go for a small price potentially. I've never played one of those things so I'm not sure really how good the experience is (the quality of the emulation, how good it hooks up to modern tv's, etc.)

If you want a high quality retro experience that's similar you could get an NES or SNES classic editions which you may or may not have heard of. They are official products from Nintendo, they'd be high quality and come with a good original style controller, guaranteed to be a good experience but you're limited to the 20-30 or so games that come preloaded on them (although both have excellent libraries of games). If you want something simple that's guaranteed to be good and plug and play that's def. an option too, although you'll pay more probably.

It really sucks that they took down the Wii marketplace.

I bought most of the classics on there and have adapters for my old NES/SNES/N64 controllers

Something like this....if its sold out they are always available through other sellers.
LINK

Or this LINK

If you are just wanting Nintendo games then I would stick with modded NES or SNES classic system that has only NES or SNES games. When you have multiple systems on one of these user interface can be a bit confusing when loading games and applying various emulators. I dont let my young kids mess with mine that has multiple systems because the can easily frick shite up.